1. Field of the Invention
The present invention relates to an information recording apparatus for recording record information such as video information, audio information or the like to be principally recorded, by reproducing address information or synchronization signal necessary for a positional retrieval when recording the record information (hereinafter, referred to as "pre-information") or rotational control information for a rotational control of the record medium, onto the record medium of postscript WO (Write Once) type on which the pre-information or the rotational control information is recorded in advance (hereafter, referred to as a DVD-R (DVD-Recordable)) among high density record media represented by the DVD whose record density is drastically improved as compared with a conventional CD (Compact Disk) and the like.
2. Description of the Related Art
There is a CD-R (CD-Recordable) as an optical disk having a record capacity similar to that of the CD, on which the pre-information is recorded beforehand and onto which the postscript information can be recorded afterward in accordance with the pre-information.
In the CD-R, at a pre-formatting step of manufacturing the CD-R, an information track (a groove track or a land track), onto which the record information is to be recorded, is wobbled into a wave shape at a frequency corresponding to a signal into which the pre-information to be recorded is beforehand FM (Frequency Modulation)-modulated, so that the pre-information is recorded.
When the record information is actually recorded onto the conventional CD-R, a wobbling frequency of the wobbled track is detected. A standard clock to rotation-control the CD-R is extracted on the basis of the detection. A drive signal to rotation-control a spindle motor for rotating the CD-R is generated on the basis of the extracted standard clock.
Moreover, as for the address information indicative of an address on the CD-R required when recording the record information, the pre-information is reproduced when recording the record information. Then, a position to be recorded is detected on the basis of the reproduced pre-information, to thereby record the record information.
On the other hand, in a case of the DVD-R which is recently being developed, an information track (for example, a groove track) in the DVD-R is wobbled at a frequency on the basis of the standard clock, so that the rotational control information is recorded thereon. In addition, the pre-information is recorded by forming a pre-pit corresponding to the pre-information on a track (for example, a land track) between the two information tracks.
However, when recording the record information onto the DVD-R, if emitting a light beam to the information track to thereby detect a signal which includes a wobbling frequency component (hereafter, referred to as a wobbling signal) of the information track, one portion of the light beam is also emitted onto the pre-pit on a track adjacent to the information track. This results in one problem that a signal corresponding to the pre-pit is mixed into the wobbling signal detected from the information track so that the wobbling signal with an excellent quality cannot be detected.
Moreover, since the signal itself corresponding to the pre-pit has an impulse characteristic (i.e., such a characteristic that a signal is uniformly distributed over a whole frequency band area), there is another problem that the signal corresponding to the pre-pit cannot be removed only by a simple filter means.